Windows 95, 98, NT and XP all have a simple registry backup mechanism that is quite reliable, although you should never simply rely on it, remember to always make a backup first!

Windows 95

In the Windows directory there are several hidden files, four of these will be SYSTEM.DAT & USER.DAT, your current registry, and SYSTEM.DA0 & USER.DA0, a backup of your registry. Windows 9x has a nice feature in that every time it appears to start successfully it will copy the registry over these backup files, so just in case something goes wrong can can restore it to a known good state. To restore the registry follow these instructions:

• Click the Start button, and then click Shut Down.
  

• Click Restart The Computer In MS-DOS Mode, then click Yes.
  

• Change to your Windows directory. For example, if your Windows directory is c:\windows, you would type the following:
  
  cd c:\windows
  
  

• Type the following commands, pressing ENTER after each one.
  (Note that SYSTEM.DA0 and USER.DA0 contain the number zero.)
  
  

  attrib -h -r -s system.dat
  attrib -h -r -s system.da0
  copy system.da0 system.dat
  attrib -h -r -s user.dat
  attrib -h -r -s user.da0
  copy user.da0 user.dat
  

• Restart your computer.
  

Following this procedure will restore your registry to its state when you last successfully started your computer.

If all else fails, there is a file on your hard disk named SYSTEM.1ST that was created when Windows 95 was first successfully installed. If necessary you could also change the file attributes of this file from read-only and hidden to archive to copy the file to C:\WINDOWS\SYSTEM.DAT.

Windows 98

To restore a registry file in Windows 98;

• Reboot the system to DOS either using your start-up disk or by using Start>Shutdown>Restart in DOS mode.

• At the DOS Prompt, type scanreg /restore (don't miss the space between "g" and "/")

• Select a date prior to the problem and follow the prompts.

Windows NT or XP

On Windows NT you can use either the "Last Known Good" option or RDISK to restore the registry to a stable working configuration.